1. Field of the Invention
The present invention relates generally to a heat sink and in particular, relates to a heat sink with heat pipes for integrated circuit package in computer system.
2. Prior Art
Continuing development of integrated circuits technology has result in that integrated circuit packages such as central processing units (CPUs) operates at a more and more high speed. Heat generated by these modern integrated circuit packages has increased commensurately. Accumulation of heat will bring on an increasing of temperature of the integrated circuit packages; consequently, result in an instability of operation or being damaged. For above reason, the heat generated by their operation must be efficiently removed in order to maintain the temperature of the integrated circuits packages within limits that will keep the operating parameters of the packages within predetermined ranges, and also prevent destruction of the device by overheating.
Various heat sink configurations for heat dissipation of integrated circuit packages are developed. For example, Taiwan patent application Nos. 89214786 and 89213022 each discloses a conventional heat sink with a base for contacting an integrated circuit package and a plurality of fins arranged on the base. Most of heat generated by the integrated circuit package is conducted to the base, and then conducted upwardly from the base to the fins. However, the fins absorb the heat from the base through a single thermal conductive path. Heat cannot be speedily transferred from the base to the fins, which results in overheating of the base. Thus, the heat generated by the integrated circuit package cannot be efficiently dissipated by the heat sink.
In order to overcome above-mentioned shortcomings, a kind of heat sink with heat pipes is designed and employed. Referring to FIG. 6, the heat sink has a base 100, two vertical U-shaped heat pipes 200 installed on the base 100 and a plurality of parallel fins 300 through which the heat pipes 200 extend. The heat sink absorbs heat generated by an integrated circuit package (not shown) by means of the base 100. Heat is transferred to the fins 300 via the heat pipes 200 for further heat dissipation. Heat accumulated in the base 100 can be speedily transferred to the fins 300 under the high thermal conductivity of the heat pipes 200, which avoids overheating of the base 100.
However, the heat pipe 200 usually has a small diameter, thus, contacting area between the heat pipes 200 and the fins 300 is limited. Moreover, the heat pipes 200 are mostly connected to the fins 300 by soldering. Operation of soldering between closed circular edges in the fins 300 and a circumference of a small-diameter heat pipe 200 is difficult. Heat conduction efficiency from the heat pipes 200 to the fins 300 is greatly affected by the quality of soldering. Consequently, heat cannot be efficiently conveyed from the heat pipes 200 to the fins 300, and utilization rate of the fins 300 is still low. Heat dissipation efficiency of the heat sink is limited.